at91: Enable slow master clock on meesc board

Normally the processor clock has a divisor of 2.
In some cases this this needs to be set to 4.
Check the user has set environment mdiv to 4 to change the divisor.

Signed-off-by: Daniel Gorsulowski <Daniel.Gorsulowski@esd.eu>
This commit is contained in:
Daniel Gorsulowski 2010-01-20 08:00:11 +01:00 committed by Tom Rix
parent 7da6923604
commit a3f3897bfd
2 changed files with 27 additions and 0 deletions

View file

@ -219,6 +219,32 @@ u32 get_board_rev(void)
}
#endif
#ifdef CONFIG_MISC_INIT_R
int misc_init_r(void)
{
char *str;
char buf[32];
/*
* Normally the processor clock has a divisor of 2.
* In some cases this this needs to be set to 4.
* Check the user has set environment mdiv to 4 to change the divisor.
*/
if ((str = getenv("mdiv")) && (strcmp(str, "4") == 0)) {
at91_sys_write(AT91_PMC_MCKR,
(at91_sys_read(AT91_PMC_MCKR) & ~AT91_PMC_MDIV) |
AT91SAM9_PMC_MDIV_4);
at91_clock_init(0);
serial_setbrg();
/* Notify the user that the clock is not default */
printf("Setting master clock to %s MHz\n",
strmhz(buf, get_mck_clk_rate()));
}
return 0;
}
#endif /* CONFIG_MISC_INIT_R */
int board_init(void)
{
/* Peripheral Clock Enable Register */

View file

@ -48,6 +48,7 @@
#define CONFIG_SKIP_LOWLEVEL_INIT
#define CONFIG_SKIP_RELOCATE_UBOOT
#define CONFIG_MISC_INIT_R /* Call misc_init_r */
#define CONFIG_ARCH_CPU_INIT